Process of severing glass or the like



y 2, 1929- F. N. CAMPBELL ET AL PROCESS OF SEVERING GLASS OR THE LIKE Filed Nov. 27. 1926 4- Sheets-Sheetbe" 50 36 Fl/RM/W/fl' CAMPBELL 91 94 33 Mm Hume i315 Jams Mmrr y 1929- F. N. CAMPBELL ET AL- 4 1.719.588

v PROCESS of savanna emss on THE LIKE Filed Nov. 27. 1926 4 Sheets-Sheet 5 .Z/RMAI/MUHMPBELL JuzzsA/mrr y 2, 1929- F. N. CAMPBELL ET AL 1.719.588'

PROCESS OF SEVERING GLASS OR THE LIKE Filed Nov. 27. 1926 4 Sheets-Sheet 4 anmntow a o JULES MYATI Hem/v mew/m:

7 Pa -ad July 2, 1929.

, UNITED STATES.

1,7,19,588 PATENT OFFICE.

TUBMAN N. CAMPBELL, OF NEW HAVENQ ANDJULES MYATT OI' EAST HAVEN, CON- NECTICUT, ASSIGNOBS TO BESSIE L. GREGG, F FOREST HILL GARDENS, NEW YORK.

PROGESS OF SEVERING GLASS OR THE LIKE.

Applicationfiled November 27, 1926. Serial No. 151,225.

This invention relates to a process of severing materials such as sheets of glass or the like.

The cutting of glass heretofore has been a cumbersome and uncertain process. In fact, authorities in the art of glass manufacturinghave heretofore assumed and asserted that plate glass and sheet glass cannot be out commercially by any machine operation (see commercial text book on glass, etc., page 195, published in 1923 by Pittsburgh PlateGlass Company) Nevertheless, we have 'in our present invention provided a process of severing' glass along a defined line by applying 1 heat to the zone of such line and controlling the'distribution of such heat, and other conditions, in a man'ner whereby controlled expansion takes placeand the glass is accurately severed at the desired line. .We have/found 2 it satisfactory and convenient to. apply such heat by bringing a-hot ob ect or ob ects or elements,- heated electrically or otherwise, into.

contact with or into close proximity of the glass, but if desired, according to certain phases of the invention, heat may be provided by the combustion of oxidizable material placed along the line of cleavage, or by other suitable chemical action. On the other hand, in certain instances the required temperature difference may also be established by applying refrigerating means to the zone'of cut-f ting or certain areas thereofwhich may be different from the main body of theglassh We have found it preferable to v provide suitable means for supporting or suspending the glass, and in a manner such as to permit unrestrained separation of the glass parts when being severed, the heat being applied 4o along-thedesired line either along theunder side' or the upper side ofthe glass at the line ofcleavage. B

In order to quickly initiate the severing action, a nick or fault or other weakened portion may be provided at a pointon the line of cleavage where the severing action is to'start.

Such weakened portion may be formed during the manufacture of the glass, by melting with a heated element,"or mechanically by suitable abrasive or cutting means. Furthermore, although it has heretofore 4 been practically impossible to cut, split or sever glass along an irregular or'curved line without destroying or breaking away at least view one'form of machine for splitting glass one of the severed parts, the process embodyv ing our invention is applicable for use incutting glass part way across or entirely across, along astraight line, a curved line, or a line including sharp angular bends. In'such instances, the cracking action is controlled and limited to the desired lines so that both the severed parts may be used either with or withmelt through Orbreak the glass by'the resulting expansion accompanied by bending forces. However, in such attempts no provision has been made for the control of the dis tflbution of heatatthe zone of cutting and therefore even for tubular glass members theprocess was uncertain, inaccurate and time consuming, and could not be'extendecl to the problem of cutting fiat glass or cold hardened glass-in other shapes,since the glass would be shattered and the cracking would be out of control. 8 a The objects of this invention. include the provisionlof a dependable, relatively simple i and convenient process for the purposes above referred to. The invention comprises the novel process and steps of the process embodied by way of example in the procedure.

hereinafter described as illustrating a prethus cooled to a temperature substantially .which form a part of this specification.

In the drawings, Fig. 1 illustrates in plan 5- 9 by theprocess embodying our invention;

- Figs. 2 and 3 are sectional elevational views taken substantially along the line 2-2 of Fig. 1 and illustrating the parts of the ma-. chine in two difi'erent'operating positions;

Fig. 4 isa sectional view taken substantially along the line of, Fig. 3;

Fig. 5 is a sectional view taken substantially along the line 55 of Fig. 1;

Fig. 6 is a diagrammatic illustration indi- 1.05 eating 1e manner of performing our process;

- Fig. 7 and 8 are diagrammatic illustraj tions indicating the results of improper temperature control during the cutting opera tion; w

our process and are illustrative of certain particular applications of 'the process;

Fig. 11 is a sectional elevational view of another form of machine for severing glass by the process embodying our invention; and

Fig. 12 is a plan view of part of the machine shown in Fig. 11.

Referring to the drawings, the particular machines there shown for carrying out our process will now be described. A suitable supporting means such as atable is indicated at 20 upon which an extended area of glass as at 21 may be horizontally supported. The table may be provided at. each end with supporting frames as at 22 and 23. The glass may be moved on to the table in proper position for cutting, either manually or automatically and to facilitate such handling a plurality of pairs of conveyor rollers as at 24 andv25 may be provided. As shown, the rollers may be rovided with rubber peripheries as at 26 or contacting with the glass and may be mounted in pairs on suitable beating yokes as at 27. If desired, the rollers may be driven from a suitable, source of power, pulleys being provided as at 28 adapted to be rotated by suitable belts 29. With the machine shown, provision'is made for cutti g the glass alon a line coinciding with the enter portion 0 the machine, the conveyor rollers 24 and 25 being arranged at spaced points along each side of the zone of cutting.- I he yoke 27 of each pair of conveyor rollers may be secured as by bolts 30 to a member 31, whichin turn is vertically slidable along the table supporting end faame betweensuitable guide members as 'at 32 and 33. V

The conveyor rollers, together with the yokes 27 and slidable members 31, are movable vertically by the operation of lever members as at 34 pivotally mounted as at 35 upon the table end frame members and having pivotal and slidable engagement as at 36 with the members 31. The mechanism for operating thelevers 34 will be hereinafter described. The table 20 may have suitable apertures as at 37 and 38 to permit the. up and down movement of the 'conveyor rollers. When, an area of glass is to be moved onto the supporting table, the conveyor rollers are normally intheir elevated positions for contact with the glass However, after the glass is in'the desired position for cutting, theconveyor rollers may be lowered out of contact with the glass, thus bringing the, glass into contact Jwith a plurality of spaced anti-friction supporting dev1ces as at 39. These anti-friction devices have been found desirable for the purpose of permitting unrestrained separation of the glass parts when being severed and may take the form 'either' of rounded metallic surfaces over which the glass slides easily or may be in the form of rotatable balls positioned at spaced points along the table top.

The table top may be formed with a gap 40 of extended area beneath which means may be mounted for applying and controlling the heat fonefiecting the severing operation. An

and for preventing excessive sa ging thereof during the severing operation. 'uch shoulder portions are of particular value for supporting narrow strips of glass which do not fully extend over the table. At its lower edge the strip of insulation 42 extends between a pair of shoulder members 46 and 47 for respective- 1y supporting heating plates 48 and 49 as hereinafter more fully described.

The heated wire 41 as indicated in Fig. 4 may be secured at one end to a binding post 50 and connected with a lead 51 for extending to a current source. At its other end the wire may be secured to a spring member 52 for holding the wire straight and under tension when heated. The-spring member 52 may be mounted on the strip of insulation 42 and secured by suitable clamping means 53 (see Fig. 5). The spring member 52 may be formed with a suitable aperture 54 for receiving a heat insulating bushing such as a glass bead 55 through which the wire 41 is threaded. At its end the wire 41 may be provided with suitable clamping means 56 electrically connected by the wire 57 to a binding screw and terminal 58. A lead wire 59 is provided-for cooperating with the lead wire 51 in conducting the desired electrical power to the wire 41.

retained throughout the greater portion of its length in a position spaced slightly from con tact. with the glass. However, at least one point, preferably at its end, the wire 41 may be so positioned or formed with an enlargement as at 60 for contacting directly w th'the glass at a'point near where it is dBFIIGdtO initiate the severing action, the remainder of the wire extending along near and directly beneath the desired line of cleavage, although such spacing is not essential. .It 1s believed that when an attempt is made to bring the .wire into direct contact with the glass along the entire line of cleavage, such contacting is liable to be more or less irregular and at the points of direct and firm contact an excess of heat will be admitted to the glass, whereas at points of uncertain contact, not enough heat will be admitted to insure the desired uniformity of heating and the proper severmg action.

The heating plates 48 and 49 are preferably adjustably mounted to be separately movable and also movable with the heated wire 41 so that such plates may be brought intoa' desired spaced relation with the glass along the line of cleavage. Each of the heating plates may comprise a sheet of insulating material as at 61 (see Fig. 1) perforated as at 62 in order to receive an electrical resistance wire 63 threaded through the perforations. In the example shown in Fig. 1, the perforations are so spaced that at the upper side of the heating plates, strands of the heated resistance wire will extend in closely spaced relation along lines substantially perpendicular to the hot wire 41, which arrangement gives highly satisfactory results. Along the center of the machine as at 64 the heating plates are shown as being made substantially wider than at the endsof the-machine, the width gradually tapering toward each end. At the edges of the glass it is under some circumstances apparently necessary to apply less heat than is necessary at the center portions of an extended area of glass-to properly control the expansion of the glass along the cutting line, andaccordingly the tapered shape I of the heatin plates-has been found to satisable in respect thereto.

may be adjusted and fixed in the desired posifactorily' ful 11 such requirements. The re sistance wires of the two heating plates may be connected in series if desired with the terminals attached to binding screws as at 65 and 66 (see Fig. 5) for engagement respectively with lead wires 67 and 68 extending to any suitable source of electrical current.

To provide for the desired lateral adjustment of the heating plate 48, the heating plate member and the shpulder portion 46 may be vformed with cooperatin guide-Ways as 69 by which the heating pla e 48 is secured to its shoulder portion 46 but is horizontally slid- The heating plate tion by turning a thumb screw 70 rotatably secured at 71 to the shoulder portion 46. The

. heating plate 49 may be mounted in a manner similar to heating plate 48 andprovided with an adjusting'thumb screw 72. In ,order to 78 whereby both heating plates 48 and 49,

together with the heating wire 41, may be moved laterally in respect to the glass. The insulation strip 42 may be secured to the carriage member 77 by suitable screws as at 79.

The lateral position of the carriage member 77 may be adjusted and alfix'ed by a thumb screw as at 80. It will be understood that the supporting member 78 is formed with appropriate slots as indicated by dotted lines,

permitting free lateral movement of the thumb screws and 76.

The relative arrangement and dimensions of the wire'41 and the heating plates 48 and 49 and parts thereof will depend to a certain extent upon the character and thickness of the glass or other materialwhich is to be sev-..

cred. For example, in some instances it may be found desirable to mount the heating plates in a osition where they will come into a closer re ationship with the glass than is indicated in the drawings in order to heat a limited area to a higher temperature. In other cases a more extended area may be heated by moving the plates to a position further away from the glass and further away from the wire 41. The extent of the heating may be further adjusted orvaried by adjusting the current supplied. That is, various voltages may be applied to the terminals 65 and .66 depending upon the desired heatiitg effects. The desired uniformity of heating at various points along the line of cleavage may be secured by properly spacing the perpendicular lengths of resistance wire 63. It may also be found desirable to vary the temperature of the hot wire 41 as by adjusting the voltage of thesource of current supply. For example, in splitting extended areas of glass, a relatively low temperature is desirable. In such cases we prefer, to heat the wire quite hot but only to a. degree such that illuminarelatively narrow strips or for thinner glass the wire should be heated to a cherry red and if the glass is to be severed along its edge or a narrow strip is to "be trimmed oil", we have found it desirable to heat the wire red hot. The .proper temperature for'the wire, however, will vary within wide limits not only because of variations in different forms and .tion' is substantially absent. However, for

types of glass but"because of constructional features or details of the wire supporting strip and other parts of the machine, and accordingly applicants do not desire to be limited toparticular wire temperatures such as above indicated.

The supporting member 78 may be mounted upon or formed integrally with a vertically slidable member 81 receivedbetween guide strips 82 and 83. The conveyor roller operating levers 34 may be pivotally and slidably connected as at -84 to the. member 81. An operating lever 85 may be pivotally mounted upon a rock shaft 86 and pivotally.

the slidable members 31, together with theconveyor rollers, are lowered out of contact and supporting relation with the glass to bring the glass into contact with the anti friction supporting devices 39.

The rock shaft 86 may extend from the table supporting frame 23 to the support-- ing frame 22. It will be understood that the supporting frame 22 may be provided with operating levers and slidable supporting means for the conveyor rollers, the heating plates and the hot wire, similar to the arrangement mounted upon the frame member 23 and operated by the rock shaft 86. The

slidable members 31 at their upper ends may be provided with a horizontally extending bar as at 89 extending the length of the table for interconnecting the slidable members 31 at each of the frames 22 and 23. The supporting member 78 if desired may likewise be extended for interconnecting the slidable members 81. The frame members 22' and 23 may be retained in proper relationship by connecting rods as at 90.

In order to'form the desired fault or nick atthe line of cleavage, means may be provided for this purpose for engaging the glass either at its upper edge or its lower edge,

- at the time the glass is moved into cutting position upon the table. For example, as indlcated 1n Fig. 4, a hardened steel cutting wheel 91 may be pivotally mountedin a slidable bearing 92 which bearing is pressed downwardly by a spring 93 so as to bring the cutting wheel into firm but yielding'contact with the edge of the glass at the desired line of cleavage when the glass is moved into cutting position. Contact with successive pieces ofglass will cause the cutting wheel 91 to turn periodically to bring fresh cutting edge portions into operating position. The bearing 92 if desired may be supported upon a partition member 94 which retains the two severed portions of glass in spaced relation,

as the same arefmoved off the table 20.

Apiece of glass 95 is indicated" in Fig. 6.

provided with a nicked or weakened portion 96 formed at its lower edge by a suitable cutting wheel or other means.

Fig. 6 serves to further illustrate the relati've arrangementsof the various heating elements. ,The desired line of cleavage is indicated at 97. The heated cutting wire 41 ex tends along beneath this line in spaced relatioii 'thereto. The enlargement or extension 60 on the cutting wire 41 contacts directly with the glass adjacent nick 96 and insures the desired prompt starting of the cutting action. lVire heating elements are indicated at 98 and 99 respectively at each side of the wire 41 and have their active heating portions running perpendicular to the wire 41 and in spaced relation to the glass.

These active portions are indicated by the full lines, whereas the inactive portions, which extend along beneath the insulation supports of the heating plates, are indicated by dotted lines.

In operating the machine the heating plates and the hot wire are first adjusted to obtain the proper results with the particular kind-of glass to be out. The proper adjustments'may be determined either by a cut-andtry method or by reference to prior experience with the machine. The glass to be cut is then brought into the desired position on the table and when properly positioned the nick or weakened portion is formed in the manner above described. When the 0per,

ator applies pressure to'the. pedal 88, the heated elements are brpught into active position and at the same time the conveyor rollers are lowered so that the glass rests upon the anti-friction supporting devices. lVithin a few seconds the glass gevering action will start at the weakened portion and rapidly and accurately proceed along the de- During 'the severdesired line of cleavage. ing action, and also thereafter, the severed edges will rest upon the shoulder portlons 44 and 45 and will beprevented from excessive" sagging and from dropping through the gap in the table. At the same time by reason of the gap in the table the zone of cutting will be very effectively insulated from contact with heat conductive or absorptive objects.

When a heated Wire is applied along a desired line of cleavage on an extended area of glass and no particular provision is made for controlling the distribution of heat along the zone of such line, the severing action if it occurs, will notv be under the 0 erators'co'ntrol and will not ordinarily fol ow the desired ,line; By providing heating plates as above described, however, the heat radiation within and along the glass may bereadily controlled and the areas of glass each side of the cutting line may be heatedsubstantially equally when it is desired to split an extended area of glass through its m'id portion. Additional problems arise however, when it is desired to trim a narrow strip from the edge of an extended area of glass or when it is desired to split a narrow stripof glass. Because of the conditions prevailin at the edge of a large area of glass, 76%) provide but one heating plate positioned at the side of the cuttin wire opposite from the edge. Oonsiderab e care must be exer ave found it usually necessary to provides an insufficient uantit of heat, a' heated zone will be esta lishe cised in selecting a proper form and position for such single heating plate. If an excessof heat is applied, the glass in most cases will not be severed along the desired line of cleavage and along the heated cutting wire..

Instead a more or less irregular cracking will occur usually following a curved line at the side of thecutting wire op osite from the edge. For example, in Fig. 1 a iece of glass is indicated at 100 having an e ge portion 101 which is to betrimmed ofi. A hot wire 102 is laced along the desired line of cleavage. I? a heating plate is brought into proximity of the cutting zone at the side of the hot wire opposite from the glass edge, a heated zone such as-roughly indicated b the dotted lines 103 will beestablished i the heating is excessive or is applied too -ra idly. In that case the glass will usually e severed along a more or less irregular line 104 curved inwardly of the sheet of glass in respect to the hot wire. Again, if a eating plate is brought into proximity of the zone of cuttin at the side of the cutting wire opposite rom the glass edge, and such plate imately the center ofthe field or zone of expansion. When an intermediate proper perature is applied with a suitable heating plate, the line of severing ,will follow accurately the hot wire at the desired line-'of cleavage.

As above stated, our process is also applicable to the cutting of an area of glass part way across only and along a predetermined line of cleavage. .For example,.in Fig. 9 apiece of glass 107 is indicated split part way across as at 108. This may be accomplished by the use of a machine more particularly adapted for such purpose, or if desired the sive only with the desired line of cleavage."

machine above described may be used merely by allowing the heated wire to be coexten- Either. by a single operation or by a succession of operations in which the glass 1sspl1t part way across, one may split in twain an area of glass in such a way as to remove an angular piece therefrom. For example, for special urposes sharp angular p eces may be out 20m the. glass without splittlngthe glass beyond the vertex of the angle, s1nce according to our process the .sphttlng may be limited to the particular outline desired. As shown in' Fig. 10, apiece of glass 109 may splittin the glass beyond the vertex of the angle ormed at 112. The angular piece be severed along lines 110 and 111 without 1 which filled the area 113 may by our rocess be removed as an integral piece availa le for any desired use.

11 Figs. 11 and 12 a-machine designed particularly for trimming the edges of glass is illustrated. A table114 is rovided for-supporting the glass and may be equipped with conveyor rollers as at .115 and- 116 and antifriction supporting devices'as at 117 similar to the corresponding parts in the machine above described. A heated wire is indicated at 118 andmay be accompanied by a single heating plate 119. The wire.118 and the heating plate 119 may be rovided with adjustable and vertically mova 1e supporting means con structed in substantially the same manner as in the machine above described, but omitting one of the heating plates and accompanying parts. As indicated in Fig. 11, the heating plate 119 may be laterally and independently adjusted by a thumb screw 120 and vertically adjusted by a thumb screw 121. The heating plate, together with the hot wire 118 ma be adjusted laterally as a unit by thet um screw 122. The heating. elements may be raised and lowered by operating afoot pedal 123 with the associated connecting members similar in construction to the foot pedal 88 above described and its associated parts. The parts which are not herein specifically descr bed in connection with the machine of 1 Figs. 11 and 12 ma be constructed substantially according to t e correspondingparts of the machine shown in Figs. 1-5.

Apparatus for carrying out our process is. clalmed in our co ending a plication, Ser.

No. 151,224, filed ovembe'r 2 1926, and entitled .Apparatus for severing glass or the like.

While we have described our invention in considerable detail with respect to the preferred methods or processes forperforming the same, it will be understood by those skilled in the art after understanding our invention, thatvarious changes and modifications may be made without departing from the spirit and scope of the invention and weaim in the appended claims to cover all such modifications and changes as come within the spirit of the invention.

' What we claim as new and desire to secure by Letters Patent of the United States is:

1. Process of severing glass or the like along a defined line of cleavage which com- "prises forming a nick in the glass at said line and placing a heated object alon said line,

said object being in contact wit the glass adjacentsaid nick and spaced a short distance therefrom at other oints along said line.

an. area of glass 2. Process of sp ittin I along a defined line whic comprises expanding the glass by heat at said line and controlling the resulting expansion of'glass adjacent said line.

3. In a process of splitting hardened glass, the method of controlling the ex ansion of glass over areas of substantial wldth which comprises applying thereto a controlled, con: tinuing but limited amount of heat insuflicient to cause softening of the glass.

4. Process of splitting hardened glass or the like which comprises placing a heated element along the desired line of separation, and establishing a heated zone extending along the glass substantially equally to each side of said line, said zone being of a width greater than the width of the area which issubstantially heated by said element at the line of separation.

\ I 5. Process of splitting flat glass or the like along a predetermined line of-cleavage' which comprises placing an electrically heated conductor along said line having a temperature when applied such as to effect controlled splitting, the major portion of the length of condpctor-being spaced a short distance from the, g ass.

6. Process of splitting flat glass or the like along a predetermined line of cleavagewhich comprises placin an electrically heated consplitting, the conductor contacting with theductor along sai line having a temperature when applied such as to efiect controlled glass at least at one point and other portions of the length of conductor being spaced a short distance from the glass.

7. Process of splitting sheet glass or the like at a predetermined line of cleavage which comprises supporting the glass with the area adjacent said line lnsulated from objects which are effectively conductive or absorptive of heat,-warming the surface of the glass over an area including said line, and subjecting the glass at ,said line; to a temperature,

substantially uniform and continuous along the line and diflerent from that of the remainder of said area and such that controlled splitting. occurs, said warmed area extending substantially beyond the area directly heated by the application of heat at'said line, I

' 8. Process of splittin sheet glass or the like at a predetermined l1ne of cleavage which comprises supporting the glass at points spaced from said line, the area adjacent said line being suspended out of contact with heat conductive or absorptive bodies, warming the surface of the glass over an area including said line, and placing an electrically heated conductor along said line having a temperature such as to'efi'ect controlled splitting, the

temperature of said warmed area being con-- trolled independently of said conductor.

9. Process of splitting glass or the like along a predetermined lineof cleavage which comprises supporting the glass at points spaced from said line, the area adjacent said line beingsuspended out of contact with heat 'havin conductive or absorptive bodies, placing an ging thereof during thesplitting operation.

10. Process of splitting glass or the like along a predetermined line of cleavage which comprises supporting the glass at points spaced from said line, the area adjacent said line being suspended out of contact with heat conductive or absorptive bodies, subjecting the glass along said line to. atemperature difierent from that of the remainder of the glass and such that controlled splitting oc ours, and providing means immediately below and along said line to support the cleaved edges to preventsubstantial sagging thereof during the splitting operation.

11. Process-of severing silicious sheet material or the likewhich comprises establish-.

inga heated limited zone on the glass surface including the desired line of separation and subjecting the material at said line to a differcut temp'eraturewhereby the resulting controlled expansion causes splitting of the material along said line, said zone being wider than'the area heated incidentally to the ap-- plioation of the heat at said line.

12. Process of'severing glass or the like which comprises forming a fault in the glass at a point on the desired line of separation, establishing a heated zone including said line, and subjecting the material at said line to a required different temperature controlled independently of the heating of said zone whereby the resulting controlled expansion causes severance of the material along said line.

13. Process of severing glass or the like which comprises placing a heated element along the desired line of separation, andproviding additional heating means along the zone of said line for controlling the radiation within the glass of heat from said element.

14:. Process of severing glass or the like I which comprises placing a heated wire along the desired line of separation, and also 'con trolling the radiation within the glass of heat from said wire by heating the areas beside said line by placing heated wires spaced from the glass and running perpendicular to said first named wire.

15. Process of severing glass or the likewhich comprises subjecting the desired line of separation to a desired temperature and subjecting the areas adjacent said line to a difi'erent temperature by applying heat alon' spaced lines perpendicular to said line -0 separation.

. 16. Process-of severing an extended sheet of glass hich comprises subjecting the deperature, nd heating the areas adj acent sai'd sired lin of separation to the requlred tem line to a lesser temperature by ap lying heat along lines perpendicular to said ine of separation, such areas as heated near the edges ofthe glassbeing narrower than at other. points along the line of separation.

17. Process of severing an extended sheet of glass which comprises subjecting the desired line of separation to a desired temperature', and heating the areas adjacent said line to a lesser temperature, the heated areas near the ends of the line being narrower than at other points along the line of separation.

18. Process of severing glass orthe like which comprises forming a fault in the glass at a point on the desired lineof separation, subjecting the desired line of separation to a predetermined temperature, and heating the areas adjacent said line'to a different temperature, such areas as heated near the edges of the glass at the ends of the line being narrower than at other'points along the line of separation. I 1

19. Process of severing an extended sheet of glass which comprises subjecting the desired line of separation to a predetermined temperature, and heating to a different degree the areas adjacent said line, less heat being applied to such .areas near the edges of the glass than to other'areas along the line of separation.

20. Process ofsevering an extended sheet of glass which comprises subjecting the de-' sired line of separation to ahigh tempera ture, and heating the areas adjacent said line to a lesser temperatureby heated elements substantially spaced from the glass and running perpendicular to said line of separation.

21. Process of splitting glass or the like along a predetermined line of cleavage which comprises mounting the glass on anti-friction supporting means .to permit unrestralned" separation of the glass parts when being severed, and subjecting the'glass along said line to atemperature different from that of the remainder of the glass and such that controlled splitting occurs.

22 Process of splitting sheet glass or the.

like along a predetermined line of .cleavage which comprises supporting th"eglasson an'tifriction" devices to permit unrestrained separation of the'g'lass; arts when being severed and with the areliidj acent said line insulated fromobjects which are effectively conductive .or. absor t'ive of .heat, and subjecting the glass valo g 'sai'd line to a temperature dife.

ferent from that fofthe remainder of and such '1 that edntrolled splitting occ'u '23. Process of severing glass or the'l k along-a predetermined line whichv comprise v I meshe supporting the glass at points spaced from said line, forming a fault in the-edge of the glass at said line, bringing a heated wire into close proximity of the under side of the glass and along said line, and providing additional heating means along the zone of said line for controlling the radiationwithin the glass of heat from said wire.

24. Process of cutting glass comprising establishing a heated zone on the glass, and subjecting the glass along the middle of said zone to a higher temperature. such as to cause controlled severing of thg glass.

25. Process of severing a sheet of glass at a predetermined line which consists in independently controllable whereby controlled cracking of the glass occurs at said line.

27. Process of severing glass along a predetermined defined line, which compriseslsubstantially uniformly warming the surface of a substantial area of the glass contiguous to said line,and-maintainingthe lass at said line at a temperature different rom that of the glass immediately adjacent said line, Whereby'controlled cracking of the glass occurs atsaid line. i

28. Process of severing glass along a pres. determined defined line, which comprises warming the surface of the glass at least over a zone including said line, andheating-the glass at said line to a temperature suflicient to cause controlled cracking at said line before the interior of the glass ofsaid zone is warmed, said warm area extending sub,-

stantially beyond the area directly heated by the application of heat at said line.

29. Process of severing glass alonga predetermined defined line, which comprises relatively quickly and uniformly heating the is irface of the glass at: least over a zone con'- tiguous to said line, -and applying a higher temperature to theglass'contlguous said zoneat said line only.

In testimony whereof we have signed our 'ames tothis specification.

FURMAN N. CAMPBELL. J U-LES MYATT. 

